Process for preparing low molecular weight olefin (CO) polymer and polymerization catalyst used thereof

ABSTRACT

The present invention provides a process for preparing a low molecular weight olefin (co)polymer having a narrow molecular weight distribution with high productivity, by polymerizing or copolymerizing an olefin in the presence of an olefin polymerization catalyst comprising (A) a specific Group 4 transition metal compound, and (B) at least one compound selected from the group consisting of (B-1) an organometallic compound, (B-2) an organoaluminum compound, (B-3) an organoaluminum oxy-compound, and (B-4) a compound which reacts with the Group 4 transition metal compound (A) to form an ion pair; and compounds useful in that process.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of application Ser. No. 10/695,831,filed Oct. 30, 2003, which claims priority to Japanese Application No.2002-316579, filed Oct. 30, 2002, the disclosures of all of which areincorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to a process for preparing a low molecularweight olefin (co)polymer and a polymerization catalyst used therefor,more particularly, a process for preparing a low molecular weight olefin(co)polymer having a narrow molecular weight distribution with highproductivity and a polymerization catalyst used therefor.

BACKGROUND ART

An olefin low molecular weight polymer such as a polyethylene wax isused in applications such as a pigment dispersant, a resin processingaid, a printing ink additive, a paint additive, a rubber processing aidand a fiber treating agent. In addition, an olefin low molecular weightpolymer is also used in a releasing agent for toner. Recently, from aviewpoint of energy saving, a low temperature fixing toner is sought,and an appearance of a wax having better release characteristics at alow temperature, that is, a wax having a lower melting point with thesame composition and the same molecular weight is desired.

As a process for preparing such an olefin low molecular weight polymer,conventionally, a titanium catalyst has been usually used industrially.However, although the catalyst has an advantage that, in case of usingthe catalyst system, the yield of the low molecular weight polymer perunit amount of the catalyst is high, and the productivity is high, italso has a technical challenge that it is necessary to maintain a highhydrogen partial pressure in the gaseous phase in the polymerizationsystem and, as a result, a large amount of alkanes as side products areproduced.

Furthermore, the molecular weight distribution of the resulting lowmolecular weight polymer is wide and, in particular, since the lowmolecular weight polymer having a molecular weight of 1000 or smaller isgreatly sticky, it is difficult to use it in the aforementionedapplications without removing the low-molecular weight fraction.

As a method for solving these challenges, Japanese Patent Laid-OpenPublication No. 210905/1984 proposes a process for preparing a lowmolecular weight polymer using a vanadium catalyst. This publicationdescribes that a low molecular weight polymer having a narrow molecularweight distribution can be prepared under a low hydrogen partialpressure, as compared with that prepared using a titanium catalyst.However, the molecular weight distribution is not necessarilysufficient. In addition, Japanese Patent Laid-Open Publication No. JP-ANo. 78462/1985 proposes a process for preparing an ethylene wax,comprising the step of polymerizing ethylene or copolymerizing ethylenewith an α-olefin, in the presence of a metallocene catalyst comprising(A) a compound of a transition metal selected from the group consistingof Group 4 elements, Group 5 elements and Group 6 elements of theperiodic table and (B) an aluminoxane. According to this process, anethylene wax having a narrow molecular weight distribution can beprepared, but a process for preparing an ethylene wax having furtherexcellent productivity is desired.

Furthermore, Japanese Patent Laid-Open Publication No. 203410/1989 andJapanese Patent Laid-Open Publication No. 49129/1994 describepreparation of an ethylene wax using a metallocene catalyst comprising ametallocene and an aluminoxane. However, in these methods, theproductivity is not necessarily sufficient. When a polymerizingtemperature is raised, it becomes easy to remove the polymerizationheat, and the productivity can be improved, but there is a challengethat a yield of a low molecular weight polymer per unit weight of acatalyst is lowered.

Japanese Patent Laid-Open Publication No. 239414/1996 has alreadyproposed a process for preparing an ethylene wax, comprising the step of(co)polymerizing ethylene in the presence of an olefin polymerizationcatalyst comprising (A) a Group 4B transition metal compound containinga ligand having a cyclopentadienyl skeleton, (B) a compound which reactswith the (A) to form an ion pair, and (C) an organoaluminum compound.According to this process, an ethylene wax having a narrow molecularweight distribution can be prepared at high production efficiency, but aprocess for preparing an ethylene wax further excellent in theproductivity and the quality is desired.

SUMMARY OF THE INVENTION

The present inventors intensively studied in order to solve theaforementioned Challenges in the background art and, as a result, havefound that a low molecular weight olefin (co)polymer having a narrowmolecular weight distribution is obtained with high productivity bypolymerizing or copolymerizing an olefin in the presence of an olefinpolymerization catalyst containing a specific transition metal compound.

Also, we have found that, in the case that the main monomer is ethylene,a low molecular weight olefin (co)polymer having a narrow molecularweight distribution, a low melting point and a low intrinsic viscosityis obtained with very high productivity when the aforementioned(co)polymerization is performed at a temperature of 100° C. or higher.

The present invention provides a process for preparing a low molecularweight olefin (co)polymer having a narrow molecular weight distributionwith high productivity.

The present invention provides a process for preparing a low molecularweight olefin (co)polymer having a narrow molecular weight distributionwith the high productivity, comprising a step of polymerizing orcopolymerizing an olefin in the presence of a polymerization catalystcontaining a specific transition metal compound.

The present invention provides an olefin polymerization catalyst thatcan prepare a low molecular weight olefin (co)polymer having a narrowmolecular weight distribution with high productivity in the presence ofa specific transition metal compound.

Furthermore, the present invention provides a novel transition metalcompound suitable as a component for polymerizing an olefin.

More specifically, a process for preparing a low molecular weight olefin(co)polymer having a narrow molecular weight distribution with highproductivity in accordance with the present invention is:

a process for preparing a low molecular weight olefin(co)polymer bypolymerizing or copolymerizing an olefin in the presence of an olefinpolymerization catalyst comprising:

(A) a Group 4 transition metal compound represented by the followinggeneral formula (1) and, (B) at least one compound selected from thegroup consisting of (B-1) an organometallic compound, (B-2) anorganoaluminum compound, (B-3) an organoaluminum oxy-compound, and (B-4)a compound which reacts with the Group 4 transition metal compound (A)to form an ion pair;

wherein R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹², R¹³ and R¹⁴may be the same or different, and are independently selected from thegroup consisting of hydrogen, a hydrocarbon group and asilicon-containing group; each adjacent pair of substituents R¹ to R¹⁴may be taken together to form a ring; M is Ti, Zr or Hf; Y is a Group 14atom; each Q is independently selected from the group consisting of: ahalogen, a hydrocarbon group, a neutral conjugated or non-conjugateddiene having 10 or fewer carbon atoms, an anionic ligand, and a neutralligand that can be coordinated with a lone electron pair; n is aninteger of from 2 to 4; and j is an integer of from 1 to 4; wherein anintrinsic viscosity [η] of the low molecular weight olefin (co)polymermeasured in decalin at 135° C. is 0.6 dl/g or less.

In the present invention, in particular, when ethylene is a mainmonomer, the polymerization or copolymerization of an olefin at apolymerizing temperature of 100° C. or higher is a preferable embodimentof the aforementioned polymerizing process.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Preferred embodiments of the process for preparing a low molecularweight olefin (co)polymer and the polymerization catalyst used thereforin accordance with the present invention will be specifically explainedbelow.

As used herein, the term “polymerization” includes not onlyhomopolymerization but also copolymerization, and the term “polymer”includes not only a homopolymer but also a copolymer.

First, respective components constituting an olefin polymerizationcatalyst used in the present invention will be explained.

(A) Group 4 Transition Metal Compound

Among components constituting an olefin polymerization catalyst used inthe present invention, (A) a Group 4 transition metal compound isrepresented by the following general formula (1).

In the formula, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹², R¹³and R¹⁴ may be the same or different, and are independently selectedfrom the group consisting of hydrogen, a hydrocarbon group and asilicon-containing group; each adjacent pair of substituents R¹ to R¹⁴may be taken together to form a ring; M is Ti, Zr or Hf; Y is a Group 14atom; each Q is independently selected from the group consisting of: ahalogen, a hydrocarbon group, a neutral conjugated or non-conjugateddiene having 10 or fewer carbon atoms, an anionic ligand, and a neutralligand that can be coordinated with a lone electron pair; n is aninteger of from 2 to 4; and j is an integer of from 1 to 4.

In the above formula (1), the hydrocarbon group that may constitute R¹to R¹⁴ is preferably an alkyl group having 1 to 20 carbon atoms, anarylalkyl group having 7 to 20 carbon atoms, an aryl group having 6 to20 carbon atoms, or an alkylaryl group having 7 to 20 carbon atoms, andmay contain one or more ring structures.

Examples thereof include methyl, ethyl, n-propyl, isopropyl,2-methylpropyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl,1,1-diethylpropyl, 1-ethyl-1-methylpropyl, 1,1,2,2-tetramethylpropyl,sec-butyl, tert-butyl, 1,1-dimethylbutyl, 1,1,3-trimethylbutyl,neopentyl, cyclohexylmethyl, cyclohexyl, 1-methyl-1-cyclohexyl,1-adamantyl, 2-adamatyl, 2-methyl-2-adamantyl, menthyl, norbornyl,benzyl, 2-phenylethyl, 1-tetrahydronaphthyl,1-methyl-1-tetrahydronaphthyl, phenyl, naphthyl, tolyl and so on.

In the above formula (1), the silicon-containing group is preferably analkyl- or arylsilyl group having 1 to 4 silicon atoms and 3 to 20 carbonatoms, and examples thereof include trimethylsilyl,tert-butyldimethylsilyl, triphenylsilyl and so on.

In the present invention, R¹ to R¹⁴ in the above formula (1) areselected from the group consisting of hydrogen, a hydrocarbon group anda silicon-containing group, and may be the same or different from eachother. Preferable examples of a hydrocarbon group and asilicon-containing group include those as described above.

Each adjacent pair of substituents R¹ to R¹⁴ on a cyclopentadienyl ringin the above formula (1) may be taken together to form a ring.

M in the formula (1) is a Group 4 element of periodic table, that is,zirconium, titanium or hafnium, preferably zirconium.

Y is a Group 14 atom, preferably a carbon atom or a silicon atom, and nis an integer of from 2 to 4, preferably from 2 or 3, particularlypreferably 2.

Each Q is independently selected from the group consisting of a halogen,a hydrocarbon group, a neutral conjugated or non-conjugated diene having10 or fewer carbon atoms, an anionic ligand and a neutral ligand thatcan be coordinated with a lone electron pair. When Q is a hydrocarbongroup, it is more preferably a hydrocarbon group having 1 to 10 carbonatoms.

Examples of the halogen include fluorine, chlorine, bromine and iodine,and examples of the hydrocarbon group include methyl, ethyl, n-propyl,isopropyl, 2-methylpropyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl,1,1-diethylpropyl, 1-ethyl-1-methylpropyl, 1,1,2,2-tetramethylpropyl,sec-butyl, tert-butyl, 1,1-dimethylbutyl, 1,1,3-trimethylbutyl,neopentyl, cyclohexylmethyl, cyclohexyl, 1-methyl-1-cyclohexyl and soon. Examples of the neutral conjugated or non-conjugated diene having 10or fewer carbon atoms include s-cis- or s-trans-η⁴-1,3-butadiene, s-cis-or s-trans-η⁴-1,4-diphenyl-1,3-butadiene, s-cis- ors-trans-η⁴-3-methyl-1,3-pentadiene, s-cis- ors-trans-η⁴-1,4-dibenzyl-1,3-butadiene, s-cis- ors-trans-η⁴-2,4-hexadiene, s-cis- or s-trans-η⁴-1,3-pentadiene, s-cis- ors-trans 4-η⁴-ditolyl-1,3-butadiene, s-cis- ors-trans-η⁴-η⁴-1,4-bis(trimethylsilyl)-1,3-butadiene and so on. Examplesof the anionic ligand include an alkoxy group such as methoxy,tert-butoxy and phenoxy; a carboxylate group such as acetate andbenzoate; a sulfonate group such as mesylate and tosylate; and so on.Examples of the neutral ligand which can be coordinated with a loneelectron pair include an organophosphorus compound such astrimethylphosphine, triethylphosphine, triphenylphosphine anddiphenylmethylphosphine, and ethers such as tetrahydrofuran, diethylether, dioxane, 1,2-dimethoxyethane and so on. When j is an integer of 2or larger, each Q may be the same or different from any other Q.

In the formula (1), the compound has more than one (2 to 4) Y Each Y maybe the same or different from any other Y. Plural R¹³'s and plural R¹⁴'swhich bind to Y may be the same or different from each other. Forexample, plural R¹³'s which bind to the same Y may be different, orplural R¹³'s which bind to different Y's may be the same. Further, R¹³'sor R¹⁴'s may be taken together to form a ring.

Preferable examples of a Group 4 transition metal compound representedby the formula (1) include a compound represented by the followingformula (1′):

In the formula (1′), R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, andR¹² may be the same or different, and are independently selected fromthe group consisting of a hydrogen atom, a hydrocarbon group and asilicon-containing group; each of R¹³, R¹⁴, R¹⁵ and R¹⁶ is independentlya hydrogen atom or a hydrocarbon group; n is an integer of from 1 to 3and, when n is 1, not all of R¹ to R¹⁶ are hydrogen atoms and may be thesame or different from each other. Each adjacent pair of substituents R⁵to R¹² may be taken together to form a ring; R¹³ and R¹⁵ may be takentogether to form a ring, or the pair of R¹³ and R¹⁵ and the pair of R¹⁴and R¹⁶ may be taken together to form rings simultaneously; Y¹ and Y²may be the same or different from each other, and each of them is aGroup 14 atom; M is Ti, Zr or Hf; each Q is independently selected fromthe group consisting of a halogen, a hydrocarbon group, an anionicligand and a neutral ligand that can be coordinated with a lone electronpair; and j is an integer of from 1 to 4.

In the Group 4 transition compound represented by the formula (1′), anorder arranging Y¹ and singular or plural Y²′(s) may be arbitrarilyselected in spite of the above formula.

The Group 4 transition metal compound represented by the above formula(1′) is a novel compound useful for forming an olefin polymerizationcatalyst.

Examples of Group 4 transition metal compounds represented by the abovegeneral formula (1) or (1′), which is a preferable example thereof, willbe shown below, but the scope of the present invention is not limited bythem. A ligand structure of the Group 4 transition metal compoundsrepresented by the general formula (1) or (1′) except for the part ofMQ_(j) (metal part) is divided into three parts of Cp (cyclopentadienylring part), Bridge (bridging part) and Flu (fluorenyl ring part) for theconvenience of expression. Examples of respective structures of theparts and examples of a ligand structure in a combination thereof willbe shown below. In examples of Cp and Bridge, points represented byblack spots () represent points where they are connected with Bridgeand Cp, respectively.

[Examples of Cp]

[Examples of Bridge]

[Examples of Flu]

The above-exemplified Cp (cyclopentadienyl ring part), Bridge (bridgingpart) and Flu (fluorenyl ring part) may be combined arbitrarily, andeach combination of selected Cp, Bridge and Flu is a specific example ofthe ligand structure. For example, when a ligand structure is acombination of a1-b1-c2, and MQ_(j) as a metal part is ZrCl₂, thefollowing metallocene compound is exemplified.

Examples of MQ_(j) in the above formula (1) include ZrCl₂, ZrBr₂, ZrMe₂,ZrEt₂, Zr(n-Pr)₂, ZrMeEt, ZrClMe, ZrBrMe, Zr(s-trans-η⁴-1,3-butadiene),Zr(s-trans-η⁴-1,4-Ph₂-1,3-butadiene),Zr(s-trans-η⁴-3-Me-1,3-pentadiene),Zr(s-trans-η⁴-1,4-(CH₂Ph)₂-1,3-butadiene), Zr(s-trans-η⁴-2,4-hexadiene),Zr(s-trans-4-1,3-pentadiene), Zr(s-trans-η⁴-1,4-(p-tol)₂-1,3-butadiene),Zr(s-trans-η⁴-1,4-(SiMe₃)₂-1,3-butadiene), Zr(s-cis-η⁴-1,3-butadiene),Zr(s-cis-η⁴-1,4-Ph₂-1,3-butadiene), Zr(s-cis-η⁴-3-Me-1,3-pentadiene),Zr(s-cis-η⁴-1,4-(CH₂Ph)₂-1,3-butadiene), Zr(s-cis-η⁴-2,4-hexadiene),Zr(s-cis-η⁴-1,3-pentadiene), Zr(s-cis-η⁴-1,4-(p-tol)₂-1,3-butadiene),Zr(s-cis-η⁴-1,4-(SiMe₃)₂-1,3-butadiene), Zr(OTs)₂, Zr(OMs)₂, andZr(OTf)₂, and compounds in which the transition metals, zirconium, ofthe compounds described above are replaced with titanium or hafnium.

(B-1) Organometallic Compound

As the (B-1) organometallic compound used in the present invention,specifically, the following organometallic compound is used.

Dialkyl compound of a Group 2 or Group 12 metal of the periodic tablerepresented by the formula:

R^(a)R^(b)M³

(In the formula, R^(a) and R^(b) may be the same or different from eachother, and represent a hydrocarbon group having 1 to 15, preferably 1 to4 carbon atoms, and M³ is Mg, Zn or Cd.)

These organometallic compounds (B-1) may be used alone or in combinationof two or more of them.

(B-2) Organoaluminum Compound

Examples of the (B-2) organoaluminum compound constituting the olefinpolymerization catalyst include organoaluminum compounds represented bythe following general formula (7), and alkylated complexes of a Group 1metal and aluminum represented by the following general formula (8).

Organoaluminum compounds represented by:

R^(a) _(m)Al(OR^(b))_(n)H_(p)X_(q)  (7)

(In the formula, R^(a) and R^(b) may be the same or different from eachother, and represent a hydrocarbon group having 1 to 15, preferably 1 to4 carbon atoms, X represents a halogen atom, m is a number of 0<m≦3, nis a number of 0≦n<3, p is a number of 0≦p<3, q is a number of 0≦q≦3,and m+n+p+q=3.) Examples of such compounds include trimethylaluminum,triethylaluminum, triisobutylaluminum, and diisobutylaluminum hydride.

Alkylated complexes of a Group 1 metal of the periodic table andaluminum represented by:

M²AlR^(a) ₄  (8)

(In the formula, M² represents Li, Na or K, and R^(a) represents ahydrocarbon group of 1 to 15, preferably 1 to 4 carbon atoms.)

Examples of such compounds include LiAl(C₂H₅)₄, and LiAl(C₇H₁₅)₄.

Examples of the organoaluminum compound represented by the above generalformula (7) include compounds represented by the following formula (9),(10), (11) or (12).

R^(a) _(m)Al(Orb)_(3-m)  (9)

(In the formula R^(a) and R^(b) may be the same or different from eachother, and each represents a hydrocarbon group having 1 to 15,preferably 1 to 4 carbon atoms, and m is preferably a number of1.5≦m≦3.)

R^(a) _(m)AlX_(3-m)  (10)

(In the formula, R^(a) represents a hydrocarbon group having 1 to 15,preferably 1 to 4 carbon atoms, X represents a halogen atom, and m ispreferably such a number that; 0<m<3.)

R^(a) _(m)AlH_(3-m)  (11)

(In the formula, R^(a) represents a hydrocarbon group having 1 to 15,preferably 1 to 4 carbon atoms, m is preferably such a number that;2≦m≦3.)

R^(a) _(m)Al(OR^(b))_(n)Xq  (12)

(In the formula, R^(a) and R^(b) may be the same or different from eachother, and represent a hydrocarbon group having 1 to 15, preferably 1 to4 carbon atoms, X represents a halogen atom, m is a number of 0<m≦3, nis a number of 0≦n<3, q is a number of 0≦q<3, and m+n+q=3.)

More specific examples of aluminum compounds represented by the abovegeneral formula (9), (10), (11) or (12) include tri-n-alkylaluminum suchas trimethylaluminum, triethylaluminum, tri-n-butylaluminum,tripropylaluminum, tripentylaluminum, trihexylaluminum,trioctylaluminum, and tridecylaluminum; tri-branched alkylaluminum suchas triisopropylaluminum, triisobutylaluminum, tri-sec-butylaluminum,tri-tert-butylaluminum, tri-2-methylbutylaluminum,tri-3-methylbutylaluminum, tri-2-methylpentylaluminum,tri-3-methylpentylaluminum, tri-4-methylpentylaluminum,tri-2-methylhexylaluminum, tri-3-methylhexylaluminum, andtri-2-ethylhexylaluminum; tricycloalkylaluminum such astricyclohexylaluminum, and tricyclooctylaluminum; triarylaluminum suchas triphenylaluminum, and tritolylaluminum; dialkylaluminum hydride suchas diisopropylaluminum hydride, and diisobutylaluminum hydride;alkenylaluminum such as isoprenylaluminum represented by the generalformula (i-C₄H₉)_(x)Al_(y)(C₅H₁₀)_(z) (wherein x, y and z are a positivenumber, and z≦2x); alkylaluminum alkoxide such as isobutylaluminummethoxide, isobutylaluminum ethoxide, and isobutylaluminum isopropoxide;dialkylaluminum alkoxide such as dimethylaluminium methoxide,diethylaluminium ethoxide, and dibutylaluminium butoxide; alkylaluminiumsesquialkoxide such as ethylaluminium sesquiethoxide, and butylaluminiumsesquibutoxide; partially alkoxylated alkylaluminium having the averagecomposition represented by the general formula R^(a) _(2.)₅Al(OR^(b))_(0.5); alkylaluminum aryloxide such as diethylaluminumphenoxide, diethylaluminium (2,6-di-t-butyl-4-methylphenoxide),ethylaluminium bis(2,6-di-t-butyl-4-methylphenoxide), diisobutylaluminum(2,6-di-t-butyl-4-methylphenoxide), and isobutylaluminumbis(2,6-di-t-butyl-4-methylphenoxide); dialkylaluminum halide such asdimethylaluminum chloride, diethylaluminum chloride, dibutylaluminumchloride, diethylaluminum bromide, and diisobutylaluminum chloride;alkylaluminum sesquihalide such as ethylaluminum sesquichloride,butylaluminum sesquichloride, and ethylaluminum sesquichloride;partially halogenated alkylaluminum such as alkylaluminum dihalide suchas ethylaluminum dichloride, propylaluminum dichloride, andbutylaluminum dibromide; dialkylaluminum hydride such as diethylaluminumhydride, and dibutylaluminum hydride; other partially hydrogenatedalkylaluminum such as alkylaluminum dihydride such as ethylaluminumdihydride, and propylaluminum dihydride; partially alkoxylated andhalogenated alkylaluminum such as ethylaluminum ethoxychloride,butylaluminum butoxychloride, and ethylaluminum ethoxybromide; and soon.

Alternatively, compounds similar to the compounds represented by theabove general formula (7) may be used, and examples thereof includeorganoaluminum compounds in which two or more aluminum compounds areconnected through a nitrogen atom. Specific examples of such thecompound include (C₂H₅)₂AlN(C₂H₅)Al(C₂H₅)₂.

Examples of the compounds represented by the above general formula (8)include LiAl(C₂H₅)₄, and LiAl(C₇H₁₅)₄.

Alternatively, a compound from which the above organoaluminum compoundis formed in the polymerization system, for example, a combination of ahalogenated aluminum and an alkyllithium, or a combination of ahalogenated aluminum and an alkylmagnesium may be used.

Among them, organoaluminum compounds are preferable.

Organoaluminum compounds represented by the above formula (7), oralkylated complexes of a Group 1 metal and aluminum represented by theabove formula (8) may be used alone or in combination of two or more ofthem.

(B-3) Organoaluminum Oxy-Compound

(B-3) The organoaluminum oxy-compound used in the present invention maybe the conventionally known aluminoxane, or may be the benzene-insolubleorganoaluminum oxy-compound exemplified in Japanese Patent Laid-OpenPublication No. 78687/1990.

The conventionally known aluminoxane can be prepared, for example, bythe following method, and is usually obtained as a solution in ahydrocarbon solvent.

(1) A method of adding an organoaluminum compound such astrialkylaluminum to a suspension of a compound having absorbed water ora salt containing water of crystallization, for example, magnesiumchloride hydrate, copper sulfate hydrate, aluminum sulfate hydrate,nickel sulfate hydrate, or cereus chloride hydrate in a hydrocarbonmedium, to react the organoaluminum compound with the absorbed water orthe water of crystallization.

(2) A method of reacting water, ice or water vapor directly with anorganoaluminum compound such as trialkylaluminum in a medium such asbenzene, toluene, ethyl ether, or tetrahydrofuran.

(3) A method of reacting an organoaluminum compound such astrialkylaluminum with an organotin oxide such as dimethyltin oxide, anddibutyltin oxide in a medium such as decane, benzene, or toluene.

The aluminoxane may contain a small amount of an organometalliccomponent. A solvent or an unreacted organoaluminum compound may bedistilled off from a recovered solution of the aluminoxane, and thealuminoxane may be redissolved in a solvent or suspended in a poorsolvent for aluminoxane.

Examples of an organoaluminum compound used upon preparation ofaluminoxane include the same organoaluminum compounds as thoseexemplified as the organoaluminum compound of the above (B-2).

Among them, trialkylaluminum, and tricycloalkylaluminum are preferable,and trimethylaluminum is particularly preferable.

The aforementioned organoaluminum compounds may be used alone or incombination of two or more of them.

In addition, as the benzene-insoluble organoaluminum oxy-compound usedin the present invention, those compounds in which an Al componentsoluble in benzene at 60° C. is usually 10% or smaller, preferably 5% orsmaller, particularly preferably 2% or smaller in terms of Al atom, thatmeans, those compounds which is insoluble or hardly soluble in benzeneare preferable. These organoaluminum oxy-compounds (B-3) are used aloneor in combination of two or more of them.

Aluminoxane prepared from trimethylaluminum is called methylaluminoxaneor MAO, and is a compound which is used particularly frequently.

Examples of a solvent used for preparing aluminoxane include aromatichydrocarbons such as benzene, toluene, xylene, cumene, and cymene;aliphatic hydrocarbons such as pentane, hexane, heptane, octane, decane,dodecane, hexadecane, and octadecane; alicyclic hydrocarbons such ascyclopentane, cyclohexane, cycloctane, and methylcyclopentane; petroleumfractions such as gasoline, kerosene, and gas oil; and halides of theaforementioned aromatic hydrocarbons, aliphatic hydrocarbons, andalicycilc hydrocarbons, inter alia, chlorinated or brominatedhydrocarbon solvents. Furthermore, ethers such as ethyl ether andtetrahydrofuran may be used. Among these solvents, aromatic hydrocarbonsand aliphatic hydrocarbons are particularly preferable.

Examples of the organoaluminum oxy-compound used in the presentinvention also include organoaluminum oxy-compounds represented by thefollowing formula (13).

(In the formula, R^(c) represents a hydrocarbon group having 1 to 10carbon atoms, and each R^(d) independently represents a hydrogen atom, ahalogen atom or a hydrocarbon group having 1 to 10 carbon atoms.)

The organoaluminum oxy-compound containing boron represented by theabove formula (13) can be prepared by reacting alkylboronic acidrepresented by the following formula (14) and an organoaluminum compoundat a temperature of from −80° C. to room temperature for from 1 minuteto 24 hours in an inert solvent under an inert gas atmosphere.

R^(c)B(OH)₂  (14)

(In the Formula, R^(c) is as Defined Above.)

Examples of alkylboronic acid represented by the above general formula(14) include methylboronic acid, ethylboronic acid, isopropylboronicacid, n-propylboroinc acid, n-butylboronic acid, isobutylboronic acid,n-hexylboronic acid, cyclohexylboronic acid, phenylboronic acid,3,5-difluorophenylboronic acid, pentafluorophenylboronic acid, and3,5-bis(trifluoromethyl)phenylboronic acid. Among them, methylboronicacid, n-butylboronic acid, isobutylboronic acid,3,5-difluorophenylboronic acid, and pentafluorophenylboronic acid arepreferable. These are used alone or in combination of two or more ofthem.

Examples of an organoaluminum compound to be reacted with such thealkylboronic acid include the same organoaluminum compounds as thoseexemplified as the organoaluminum compound represented by the aboveformula (7) or (8).

Among them, trialkylaluminums, and tricycloalkylaluminums arepreferable, and trimethylaluminum, triethylaluminum, andtriisobutylaluminum are particularly preferable. These are used alone orin combination of two or more of them.

(B-4) Compound which Reacts with the Aforementioned Group 4 TransitionMetal Compound (A) to Form an Ion Pair

Examples of the compound (B-4) which reacts with the aforementionedGroup 4 transition metal compound (A) to form an ion pair include Lewisacids, ionic compounds, borane compounds and carborane compoundsdescribed in Japanese Patent Laid-Open Publication No. 1-501950/1989,Japanese Patent Laid-Open Publication No. 502036/1989, Japanese PatentLaid-Open Publication No. 179005/1991, Japanese Patent Laid-OpenPublication No. 179006/1991, Japanese Patent Laid-Open Publication No.207703/1991, Japanese Patent Laid-Open Publication No. 207704/1991, andU.S. Pat. No. 5,321,106.

Examples of the Lewis acid include compounds represented by BR₃ (R is aphenyl group optionally having a substituent such as fluorine, a methylgroup, and a trifluoromethyl group, fluorine or an alkyl group such asmethyl group or isobutyl group.) such as trifluoroboron, triphenylboron,tris(4-fluorophenyl)boron, tris(3,5-difluorophenyl)boron,tris(4-fluoromethylphenyl)boron, tris(pentafluorophenyl)boron,tris(p-tolyl)boron, tris(o-tolyl)boron, tris(3,5-dimethylphenyl)boron,trimethylboron, and triisobutylboron.

Examples of the ionic compounds include compounds represented by thefollowing formula (2):

In the formula, examples of R^(e+) include H⁺, carbenium cation, oxoniumcation, ammonium cation, phosphonium cation, cyclopentyltrienyl cation,and ferrocenium cation having a transition metal. Each of R^(f), R^(g),R^(h) and R^(i) may be the same or different from each other, and is anorganic group, preferably an aryl group or a substituted aryl group.

Examples of the carbenium cation include tri-substituted carbeniumcations such as triphenylcarbenium cation, tris(methylphenyl)carbeniumcation, and tris(dimethylphenyl)carbenium cation.

Examples of the ammonium cation include trialkylammonium cations such astrimethylammonium cation, triethylammonium cation, tri(n-propyl)ammoniumcation, triisopropylammonium cation, tri(n-butyl)ammonium cation, andtriisobutyl ammonium cation; N,N-dialkylanilinium cations such asN,N-dimethylanilinium cation, N,N-diethylanilinium cation, andN,N-2,4,6-pentamethylanilinium cation; and dialkylammonium cations suchas diisopropylammonium cation, and dicyclohexylammonium cation.

Examples of the phosphonium cation include triarylphosphonium cationssuch as triphenylphosphonium cation, tris(methylphenyl)phosphoniumcation, and tris(dimethylphenyl)phosphonium cation.

Among the examples described above, as R^(e), carbenium cations andammonium cations are preferable, and triphenylcarbenium cation,N,N-dimethylanilinium cation and N,N-diethylanilinium cation areparticularly preferable.

Examples of a carbenium salt include triphenylcarbeniumtetraphenylborate, triphenylcarbenium tetrakis(pentafluorophenyl)borate,triphenylcarbenium tetrakis(3,5-ditrifluoromethylphenyl)borate,tris(4-methylphenyl)carbenium tetrakis(pentafluorophenyl)borate, andtris(3,5-dimethylphenyl)carbenium tetrakis(pentafluorophenyl)borate.

Examples of an ammonium salt include a trialkyl-substituted ammoniumsalt, an N,N-dialkylanilinium salt, and a dialkylammonium salt.

Examples of a tri-alkyl substituted ammonium salt includetriethylammonium tetraphenylborate, tripropylammonium tetraphenylborate,tri(n-butyl)ammonium tetraphenylborate, trimethylammoniumtetrakis(p-tolyl)borate, trimethylammonium tetrakis(o-tolyl)borate,tri(n-butyl)ammonium tetrakis(pentafluorophenyl)borate, triethylammoniumtetrakis(pentafluorophenyl)borate, tripropylammoniumtetrakis(pentafluorophenyl)borate, tripropylammoniumtetrakis(2,4-dimethylphenyl)borate, tri(n-butyl)ammoniumtetrakis(3,5-dimethylphenyl)borate, tri(n-butyl)ammoniumtetrakis(4-trifluoromethylphenyl)borate, tri(n-butyl)ammoniumtetrakis(3,5-ditrifluoromethylphenyl)borate, tri(n-butyl)ammoniumtetrakis(o-tolyl)borate, dioctadecylmethylammonium tetraphenylborate,dioctadecylmethylammonium tetrakis(p-tolyl)borate,dioctadecylmethylammonium tetrakis(o-tolyl)borate,dioctadecylmethylammonium tetrakis(pentafluorophenyl)borate,dioctadecylmethylammonium tetrakis(2,4-dimethylphenyl)borate,dioctadecylmethylammonium tetrakis(3,5-dimethylphenyl)borate,dioctadecylmethylammonium tetrakis(4-trifluoromethylphenyl)borate,dioctadecylmethylammonium tetrakis(3,5-ditrifluoromethylphenyl)borate,and dioctadecylmethylammonium.

Examples of the N,N-dialkylanilinium salt include N,N-dimethylaniliniumtetraphenylborate, N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate, N,N-dimethylaniliniumtetrakis(3,5-ditrifluoromethylphenyl)borate, N,N-diethylaniliniumtetraphenylborate, N,N-diethylaniliniumtetrakis(pentafluorophenyl)borate, N,N-diethylaniliniumtetrakis(3,5-ditrifluoromethylphenyl)borate,N,N-2,4,6-pentamethylanilinium tetraphenylborate, andN,N-2,4,6-pentamethylanilinium tetrakis(pentafluorophenyl)borate.

Examples of the dialkylammonium salt include di(1-propyl)ammoniumtetrakis(pentafluorophenyl)borate, and dicyclohexylammoniumtetrafluoroborate.

Further examples include ferrocenium tetrakis(pentafluorophenyl)borate,triphenylcarbenium pentaphenylcyclopentadienyl complex,N,N-diethylanilinium pentaphenylcyclopentadienyl complex, boratecompounds represented by the following formula (3) or (4), boratecompounds containing active hydrogen represented by the followingformula (5), and borate compounds containing a silyl group representedby the following formula (6).

(In the formula, Et represents an ethyl group.)

[B-Q_(n)(G_(q)(T-H)_(r))_(z)]⁻A⁺  (5)

In the formula (5), B represents boron. G represents a multi-bindinghydrocarbon radical, examples of a preferable multi-binding hydrocarboninclude alkylene having 1 to 20 carbon atoms, allylene, ethylene, andalkalylene radicals, and preferable examples of G include phenylene,bisphenylene, naphthalene, methylene, ethylene, propylene,1,4-butadiene, and p-phenylenemethylene. The multi-binding radical G hasr+1 bonds, that is, one bond binds to the borate anion, and other rbonds of G bind to the (T-H) groups. A⁺ is a cation.

T in the above formula (5) represents O, S, NR^(j), or PR^(j), R^(j)represents a hydrocarbanyl radical, a trihydrocarbanylsilyl radical, atrihydrocarbanylgermanium radical, or hydride, and q is an integer of 1or larger, preferably 1. Examples of the T-H group include —OH, —SH,—NR^(j)H, and —PR^(j)H, wherein R^(j) is a hydrocarbinyl radical having1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, or hydrogen.Examples of preferable R^(j) group include alkyl, cycloalkyl, allyl, andallylalkyl, and alkylalkyl groups having 1 to 18 carbon atoms. —OH, —SH,—NR^(j)H or —PR^(j)H may be, for example, —C(O)—OH, —C(S)—SH,—C(O)—NR^(j)H, or C(O)—PR^(j)H. The most preferable group having activehydrogen is —OH group. Q can be hydride, or a dihydrocarbylamide,preferably a dialkylamide, a halide, a hydrocarbyl oxide, an alkoxide,an allyloxide, a hydrocarbyl, or a substituted hydrocarbyl radical. Inthe formula, n+z is 4.

Examples of [B-Q_(n)(G_(q)(T-H)_(r))_(z)] of the above formula (5)include triphenyl(hydroxyphenyl)borate,diphenyl-di(hydroxyphenyl)borate, triphenyl(2,4-dihydroxyphenyl)borate,tri(p-tolyl)(hydroxyphenyl)borate,tris(pentafluorophenyl)(hydroxyphenyl)borate,tris(2,4-dimethylphenyl)(hydroxyphenyl)borate,tris(3,5-dimethylphenyl)(hydroxyphenyl)borate,tris[3,5-di(trifluoromethyl)phenyl](hydroxyphenyl)borate,tris(pentafluorophenyl)(2-hydroxyethyl)borate,tris(pentafluorophenyl)(4-hydroxybutyl)borate,tris(pentafluorophenyl)(4-hydroxycyclohexyl)borate,tris(pentafluorophenyl)[4-(4-hydroxyphenyl)phenyl]borate, andtris(pentafluorophenyl)(6-hydroxy-2-naphthyl)borate. The most preferableexample is tris(pentafluorophenyl)(4-hydroxyphenyl)borate. Furthermore,compounds obtained by substituting the OH groups of the aforementionedborate compounds with —NHR^(j) (wherein, R^(j) is methyl, ethyl, ort-butyl) are also preferable.

Examples of A⁺, which is a countercation of the borate compound, includea carbonium cation, a tropylium cation, an ammonium cation, an oxoniumcation, a sulfonium cation, and a phosphonium cation. Further examplesinclude positive ions of metals and positive ions of organometallics,which can easily be reduced. Examples of these cations include atriphenylcarbonium ion, a diphenylcarbonium ion, a cycloheptatrinium,indenium, triethylammonium, tripropylammonium, tributylammonium,dimethylammonium, dipropylammonium, dicyclohexylammonium,trioctylammonium, N,N-dimethylammonium, diethylammonium,2,4,6-pentamethylammonium, N,N-dimethylphenylammonium,di-(i-propyl)ammonium, dicyclohexylammonium, triphenylphosphonium,triphosphonium, tridimethylphenylphosphonium,tri(methylphenyl)phosphonium, a triphenylphosphonium ion, atriphenyloxonium ion, a triethyloxonium ion, pyrinium, a silver ion, agold ion, a platinum ion, a copper ion, a palladium ion, a mercury ion,and a ferrocenium ion. Inter alia, an ammonium ion is preferable.

[B-Q_(n)(G_(q)(S_(i)R^(k)R^(l)R^(m))_(r))_(z)]⁻A⁺  (6)

In the formula (6), B represents boron. G represents a multi-bindinghydrocarbon radical. Preferable examples of the multi-bindinghydrocarbon include alkylene, allylene, ethylene, and alkalyleneradicals having 1 to 20 carbon atoms, and preferable examples of Ginclude phenylene, bisphenylene, naphthalene, methylene, ethylene,propylene, 1,4-butadiene, and p-phenylenemethylene. The multi-bindingradical G has r+1 bonds, that is, one bond binds to the borate anion,and other r bonds bind to the (SiR^(k)R^(l)R^(m)) groups. A⁺ is acation.

Each of R^(k), R^(l) and R^(m) in the above formula independentlyrepresents a hydrocarbanyl radical, a trihydrocarbanylsilyl radical, atrihydrocarbanylgermanium radical, hydrogen radical, an alkoxy radical,a hydroxyl radical or a halogen compound radical. R^(k), R^(l) and R^(m)may be the same or independent. Q can be a hydride, or adihydrocarbylamide, preferably a dialkylamide, a halide, a hydrocarbyloxide, an alkoxide, an allyl oxide, a hydrocarbyl, or substitutedhydrocarbyl radical, more preferably pentafluorobenzyl radical. In theformula, n+z is 4.

Examples of [B-Q_(n)(G_(q)(S_(i)R^(k)R^(l)R^(m))_(r))_(z)]⁻ in the aboveformula (6) include triphenyl (4-dimethylchlorosilylphenyl)borate,diphenyl-di(4-dimethylchlorosilylphenyl)borate,triphenyl(4-dimethylmethoxysilylphenyl)borate,tri(p-tolyl)(4-triethoxysilylphenyl)borate,tris(pentafluorophenyl)(4-dimethylchlorosilylphenyl)borate,tris(pentafluorophenyl)(4-dimethylmethoxysilylphenyl)borate,tris(pentafluorophenyl)(4-trimethoxysilylphenyl)borate, andtris(pentafluorophenyl)(6-dimethylchlorosilyl-2-naphthyl)borate.

Examples of A⁺, which is a countercation of the borate compound, includethe same A⁺'s as those in the above formula (5).

Examples of the borane compound include salts of anions such asdecaborane, bis[tri(n-butyl)ammonium]nonaborate,bis[tri(n-butyl)ammonium]decaborate,bis[tri(n-butyl)ammonium]undecaborate,bis[tri(n-butyl)ammonium]dodecaborate,bis[tri(n-butyl)ammonium]decachlorodecaborate, andbis[tri(butyl)ammonium]dodecachlorododecaborate; and salts of metalboran anions such as tri(n-butyl)ammoniumbis(dodecahydridedodecaborate)cobaltate (III), andbis[tri(n-butyl)ammonium]bis(dodecahydridedodecaborate)nickelate (III).

Examples of the carborane compound include salts of anions such as4-carbanonaborane, 1,3-dicarbanonaborane, 6,9-dicarbadecaborane,dodecahydride-1-phenyl-1,3-dicarbanonaborane, dodecahydride-1-methyl-1,3-dicarbanonaboarne,undecahydride-1,3-dimethyl-1,3-dicarbanonaborane,7,8-dicarbaundecaborane, 2,7-dicarbaundecaborane,undecahydride-7,8-dimethyl-7,8-dicarbaundecaborane,dodecahydride-11-methyl-2,7-dicarbaundecaborane, tri(n-butyl)ammonium1-carbadecaborate, tri(n-butyl)ammonium 1-carbaundecaborate,tri(n-butyl)ammonium 1-carbadodecaborate, tri(n-butyl)ammonium1-trimethylsilyl-1-carbadecaborate, tri(n-butyl)ammoniumbromo-1-carbadodecaborate, tri(n-butyl)ammonium 6-carbadecaborate,tri(n-butyl)ammonium 6-carbadecaborate, tri(n-butyl)ammonium7-carbaundecaborate, tri(n-butyl)ammonium 7,8-dicarbaundecaborate,tri(n-butyl)ammonium 2,9-dicarbaundecaborate, tri(n-butyl)ammoniumdodecahydride-8-methyl-7,9-dicarbaundecaborate, tri(n-butyl)ammoniumundecahydride-8-ethyl-7,9-dicarbaundecaborate, tri(n-butyl)ammoniumundecahydride-8-butyl-7,9-dicarbaundecaborate, tri(n-butyl)ammoniumundecahydride-8-allyl-7,9-dicarbaundecaborate, tri(n-butyl)ammoniumundecahydride-9-trimethylsilyl-7,8-dicarbaundecaborate, andtri(n-butyl)ammonium undecahydride-4,6-bromo-7-carbaundecaborate; andsalts of metal carborane anions such as tri(n-butyl)ammoniumbis(nonahydride-1,3-dicarbanonaborate)cobaltate(III),tri(n-butyl)ammoniumbis(undecahydride-7,8-dicarbaundecaborate)ferrate(III),tri(n-butyl)ammoniumbis(undecahydride-7,8-dicarbaundecaborate)cobaltate(III),tri(n-butyl)ammoniumbis(undecahydride-7,8-dicarbaundecaborate)nickelate(III),tri(n-butyl)ammoniumbis(undecahydride-7,8-dicarbaundecaborate)cuprate(III),tri(n-butyl)ammoniumbis(undecahydride-7,8-dicarbaundecaborate)aurate(III),tri(n-butyl)ammoniumbis(nonahydride-7,8-dimethyl-7,8-dicarbaundecaborate)ferrate (III),tri(n-butyl)ammoniumbis(nonahydride-7,8-dimethyl-7,8-dicarbaundecaborate)chromate(III),tri(n-butyl)ammoniumbis(tribromooctahydride-7,8-dicarbaundecaborate)cobaltate (III),tris[tri(n-butyl)ammonium]bis(undecahydride-7-carbaundecaborate)chromate(III),bis[tri(n-butyl)ammonium]bis(undecahydride-7-carbaundecaborate)manganate(IV),bis[tri(n-butyl)ammonium]bis(undecahydride-7-carbaundecaborate)cobaltate (III), andbis[tri(n-butyl)ammonium]bis(undecahydride-7-carbaundecaborate)nickelate(IV).

Two or more kinds of compounds (B-4) which react with the aforementionedGroup 4 transition metal compound (A) to form an ion pair may be used bymixing them.

In preparation of an olefin polymerization catalyst of the presentinvention, a carrier can be used if necessary. The carrier is usually aninorganic or organic compound, and is granular or fine particle solid.Among them, examples of the inorganic compound include porous oxides,inorganic chlorides, clays, clay minerals and ion-exchanging layercompounds.

As the porous oxide, specifically, SiO₂, Al₂O₃, MgO, ZrO, TiO₂, B₂O₃,CaO, ZnO, BaO, or ThO₂, or a compound oxide or a mixture containingthem, for example, natural or synthetic zeolite, SiO₂—MgO, SiO₂—Al₂O₃,SiO₂—TiO₂, SiO₂—V₂O₅, SiO₂—Cr₂O₃, and SiO₂—TiO₂—MgO can be used.

In the present invention, an olefin low molecular weight polymer isprepared by polymerizing an olefin alone, or copolymerizing olefins inthe presence of the aforementioned olefin polymerization catalyst.

Herein, examples of the olefin include olefins having 2 to 20 carbonatoms, preferably 2 to 16 carbon atoms, such as ethylene, propylene,1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene,1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene,1-hexadecene, 1-octadecene, and 1-eicocene. These olefins having 2 to 20carbon atoms may be used by arbitrarily combining two or more species.

It is preferable that at least one of olefins to be polymerized isethylene, propylene, 1-octene, 1-decene, 1-dodecene or 1-tetradecene.Particularly preferable are homopolymerization of ethylene,copolymerization of ethylene and other olefin, homopolymerization ofpropylene, homopolymerization of 1-octene, homopolymerizaiton of1-decene, homopolymerization of 1-dodecene and homopolymerization of1-tetradecene.

Specific modes for preparing the olefin low molecular weight polymer ofthe present invention will be explained in detail below.

In the present invention, a polymerization reaction is performed in ahydrocarbon medium. Examples of such the hydrocarbon medium includealiphatic hydrocarbons such as propane, butane, pentane, hexane,heptane, octane, decane and dodecane; alicyclic hydrocarbons such ascyclopentane, cyclohexane, and methylcyclopentane; aromatic hydrocarbonssuch as benzene, toluene, and xylene; halogenated hydrocarbons such asethylene chloride, chlorobenzene, and dichloromethane; and petroleumfractions such as gasoline, kerosene, and gas oil. Furthermore, theolefins used for polymerization may be used.

In the present invention, polymerization is performed in the presence ofsuch an olefin polymerization catalyst. In this case, the Group 4transition metal compound (A) is used in an amount in a range of usuallyfrom 10⁻⁸ to 10⁻² gram atom/liter, preferably from 10⁻⁷ to 10⁻³ gramatom/liter in terms of the concentration of the transition metal atom inthe polymerizing reaction system.

The component (B-1) is used in such an amount that the molar ratio ofthe component (B-1) to the total transition metal atom (M) in thecomponent (A) [(B-1)/M] is usually in the range of from 0.01 to 5,000,preferably from 0.05 to 2,000. The component (B-2) is used in such anamount that the molar ratio of the component (B-2) to the totaltransition metal atom (M) in the component (A) [(B-2)/M] is usually inthe range of from 100 to 25,000, preferably from 500 to 10,000. Thecomponent (B-3) is used in such an amount that the molar ratio of thealuminum atom in the component (B-3) and the total transition metal (M)in the component (A) [(B-3)/M] is usually in the range of from 10 to5,000, preferably from 20 to 2,000. The component (B-4) is used in suchan amount that the molar ratio of the component (B-4) to the transitionmetal atom (M) in the component (A) [(B-4)/M] is usually in the range offrom 1 to 50, preferably 1 to 20.

When olefins are copolymerized in an arbitrary combination, thecomposition of the olefins as raw materials can be appropriatelyselected, depending the type of the low molecular weight olefin(co)polymer to be obtained. For example, in copolymerization usingethylene as a main monomer, it is preferable that the content ofethylene in raw material olefins is in the range of usually from 60 to100 mol %, preferably from 70 to 100 mol %, and the content of the otherolefin(s) is in the range of usually from 0 to 40 mol %, preferably from0 to 30 mol %.

In the present invention, it is preferable that polymerization isperformed at a temperature in the range of from 50 to 250° C. Whenethylene is used as a main monomer, it is desirable that polymerizationis performed at a temperature in the range of preferably from 100 to250° C., more preferably from 120 to 250° C., particularly preferablyfrom 130 to 200° C.

When a polymerization temperature is in the aforementioned range, it iseasy to remove the heat in the polymerization system, and a heat removaldevice can be miniaturized. In addition, even with the same heat removaldevice, since the heat removing efficacy is enhanced, the productivitycan be improved. Furthermore, since polymerization is performed at ahigh temperature, even when the polymer concentration is increased, thesolution viscosity is not increased so much, thus the stirring powerrequired can be reduced, and the polymerization can be performed at highconcentration, thereby improving the productivity.

Usually, when an olefin is (co)polymerized, the heat is removed bycirculating a solvent in order to stabilize the polymerizingtemperature. In a heat removal device usually used herein, when anamount of heat to be removed is the same, as a polymerizationtemperature grows higher, a heat transfer area can generally be madesmaller. The effect thereof varies depending on the conditions such as acooling medium and so on. For example, when a simple countercurrent-typeheat exchanger employing cooling water is used, in the case where apolymerizing temperature is 100° C., a necessary heat transfer area canbe reduced to about ½ of that required in a polymerization at atemperature of 70° C. As described above, when a polymerizationtemperature is raised, the heat transfer area required can be madesmaller, and a heat removal device can be miniaturized, thus, equipmentcost can be reduced.

It is preferable that the average residence time (polymerizing time) is2 hours or shorter, preferably 1 hour or shorter. The polymerizingpressure is usually in a range of from atmospheric pressure to 100kg/cm², preferably from atmospheric pressure to 50 kg/cm², morepreferably from atmospheric pressure to 40 kg/cm².

The molecular weight of the resulting low molecular weight olefin(co)polymer can be controlled by an amount of hydrogen supplied to thepolymerization reaction system and/or the polymerizing temperature. Theamount of hydrogen to be supplied to the polymerization reaction systemis in the range of usually from 0.01 to 2, preferably from 0.05 to 1, interms of the molar ratio of hydrogen to the olefin.

In the present invention, a low molecular weight olefin (co)polymer isobtained by treating the polymerization products mixture aftercompletion of the polymerization reaction according to the conventionalmethod.

A molecular weight distribution (Mw/Mn) of the low molecular weightolefin (co)polymer of the present invention measured by gel permeationchromatography (GPC) is usually 3 or smaller, preferably 2.5 or smaller.

An intrinsic viscosity [η] of the low molecular weight olefin(co)polymer of the present invention measured at 135° C. in decalin isin the range of 0.60 dl/g or smaller, preferably 0.40 dl/g or smaller,more preferably from 0.005 to 0.40 dl/g, further preferably from 0.005to 0.35dl/g, particularly preferably from 0.01 to 0.30 dl/g. Among thepolymers above, a low molecular weight olefin (co)polymer using ethyleneas a main monomer is usually called ethylene wax. It is preferable thatthe content of an ethylene component unit therein is in the range offrom 80 to 100 mol %, preferably from 85 to 100 mol %. It is preferablethat the content of an olefin component unit having 3 or more carbonatoms is in the range of from 0 to 20 mol %, preferably from 0 to 15 mol%. A melting point of the ethylene wax obtained in the present inventionis usually 132° C. or lower.

According to the present invention, a low molecular weight olefin(co)polymer can be prepared with high productivity. In addition, when apolymerizing temperature is 100° C. or higher, a low molecular weightolefin (co)polymer having a narrow molecular weight distribution and alow melting point can be prepared with high productivity. Furthermore, aheat removal device can be miniaturized, the equipment cost can bereduced and, at the same time, the residence time can be shortened.

The novel Group 4 transition metal compound represented by theaforementioned general formula (1′) can be prepared, for example, by theprocess described in J. Organomet. Chem., 361, 37 (1998). A specificprocess will be shown below, without limiting the scope of the inventionin any way.

For example, the compound of the general formula (1′) can be prepared bythe following steps.

First, a precursor compound [20] of the general formula (1′) can beprepared by the method of the following process [A] or [B].

Process [A]:

Process [B]:

(In the formula, R¹ to R¹⁶, and Y are same as defined in the generalformula (1′), L is an alkali metal, and each of Z¹ and Z² is a halogenor an anionic ligand, and may be the same or different from each other.)

Further, a precursor of a cyclopentadienyl ligand of the formula (1′),for example, (24) wherein each of R² and R⁴ is a hydrogen atom in theprecursor, can be prepared selectively by the following Process [C].

Process [C]:

(In the formula, R¹ and R³ are same as defined in the general formula(1′), M¹ is an alkali metal or an alkaline earth metal, Z³ is the sameas R³, or a halogen or an anionic ligand, and e is a valence number ofM¹.)

In addition, as a substitute process for producing (24), there are thefollowing Process [D] and Process [E]. In these processes, an isomer,wherein R¹ and R³ are adjacent to each other in (24), is produced as aside product in some cases. Therefore, the Process [D] and the Process[E] can be employed, depending on a combination of R¹ and R³ and thereaction conditions, as far as the isomer is not produced as a sideproduct.

Process [D]:

Process [E]:

(In the formula, R¹ and R³ are same as defined in the general formula(1′), L is an alkali metal, and Z¹ is a halogen or an anionic ligand.)

Furthermore, when R³ is a substituent represented by CR¹⁷R¹⁸R¹⁹, (24)may also be prepared by the following Process [F].

Process [F]:

(In the formula, R¹ is as defined in the general formula (1′), each ofR¹⁷, R¹⁸ and R¹⁹ is independently selected from hydrogen, a hydrocarbongroup and a silicon-containing hydrocarbon group, and may be the same ordifferent from each other, and L is an alkali metal.)

Also in this process, since an isomer of (24) wherein R¹ and R³ areadjacent to each other is produced as a side product in some cases, theProcess [F] can be employed, depending on a combination of R¹ and R³ andthe reaction conditions, as far as the isomer is not produced as a sideproduct.

Examples of the alkali metal used in the reactions of the aboveProcesses [A] to [F] include lithium, sodium and potassium and examplesof the alkaline earth metal include magnesium and calcium. In addition,examples of the halogen include fluorine, chlorine, bromine and iodine.Examples of the anionic ligand include alkoxy groups such as methoxy,tert-butoxy and phenoxy; carboxylate groups such as acetate andbenzoate; sulfonate groups such as mesylate and tosylate; and so on.

Next, an example of preparing a metallocene compound from the precursorcompounds of the general formula (20) will be shown. However, this doesnot limit the scope of the invention, and the metallocene compound maybe prepared by appropriately selecting other processes.

The precursor compound of the general formula (20) obtained by thereaction of the Process [A] or [B] is contacted with an alkali metal, analkali metal hydride or an organic alkali metal at a reactiontemperature in the range of from −80 to 200° C. in an organic solvent toobtain a dialkali metal salt.

Examples of the organic solvent used in the above reaction includealiphatic hydrocarbons such as pentane, hexane, heptane, cyclohexane anddecalin; aromatic hydrocarbons such as benzene, toluene and xylene;ethers such as THF, diethyl ether, dioxane and 1,2-dimethoxyethane;halogenated hydrocarbons such as dichloromethane and chloroform; and soon.

Example of the alkali metal used in the above reaction include lithium,sodium, potassium and so on, examples of the alkali metal hydrideinclude sodium hydride, potassium hydride and so on, and examples of theorganic alkali metal include methyllithium, butyllithium, phenyllithiumand so on.

Then, a metallocene compound represented by the general formula (1′) canbe synthesized by reacting the aforementioned dialkali metal salt with acompound represented by the following general formula (33) in an organicsolvent.

MZ_(k)  (33)

(In the formula, M is a metal selected from Group 4 of the PeriodicTable, each Z may be independently selected from a halogen, an anionicligand and a neutral ligand which can be coordinated with a loneelectron pair, and k is an integer of 3 to 6.)

Preferable examples of the compound represented by the general formula(33) include trivalent or tetravalent titanium fluoride, chloride,bromide and iodide; tetravalent zirconium fluoride, chloride, bromideand iodide; tetravalent hafnium fluoride, chloride, bromide and iodide;and complexes of these compounds and ethers such as THF, diethyl ether,dioxane and 1,2-dimethoxyethane.

In addition, examples of the organic solvent to be used include those asdescribed above. A reaction of the dialkali metal salt and the compoundrepresented by the general formula (33) is preferably performed by anequimolar reaction, and can be performed at a reaction temperature in arange of from −80 to 200° C. in the aforementioned organic solvent.

The metallocene compound obtained in the reaction can be isolated andpurified by a method such as extraction, recrystallization orsublimation. In addition, the bridged metallocene compound of thepresent invention obtained by such a process can be identified by usingan analyzing procedure such as proton nuclear magnetic resonancespectrum, ¹³C nuclear magnetic resonance spectrum, mass spectrometry orelementary analysis.

Since the low molecular weight olefin (co)polymer obtained by thepresent invention, in particular, the low-molecular weight ethylene(co)polymer has a narrow molecular weight distribution and a low meltingpoint, the polymer can be suitably used in utilities such as a paintmodifier, a glazing agent, a pigment dispersant (in particular, a rawmaterial for pigment master batch), a lubricant for polyvinyl chloride,a resin molding lubricant, a rubber processing aid, a releasing agentfor toner, a paper improver, an ink anti-abrasion agent, a fiberprocessing aid, a hot melt adhesive additive, an electrical insulator, anatural wax component, an asphalt flowability improver, various oilhardeners, a communication cable filler, a raw material for moistureproof coating agent, a peelability imparting agent for paper coating, apolymer emulsifying aid for suspension or emulsion polymerization, abase material for antistatic or weathering agent, an automobile engineoil, a gear oil, ATF, a base oil and a viscosity index improver for theindustrial lubricant, a base oil for grease, a metal processing oil, arubber/resin modifier, a releasing agent for aluminum die casting, afuel oil additive, a paint, and an ink modifier.

EXAMPLES

The present invention will be more specifically explained below by wayof Examples, but the present invention is not limited by these Examples.

The physical properties and the characteristics of the resultingpolymers were measured by the following methods.

[Weight average molecular weight (Mw), number average molecular weight(Mn)]

These molecular weights were measured using GPC-150C (manufactured byWaters Corporation) as follows: separation columns used were TSKgelGMH6-HT and TSKgel GMH6-HTL, the column had a size of 7.5 mm in innerdiameter and 600 mm in length, the column temperature was 140° C., themobile phase was o-dichlorobenzene (Wako Pure Chemical Industries, Ltd.)and 0.025 wt. % of BHT(Takeda Chemical Industries, Ltd.) as anantioxidant, the mobile phase was moved at 1.0 ml/min, the sampleconcentration was 0.1 wt. %, the sample injection amount was 500 μl, andthe detector used was a differential refractometer. As a standardpolystyrene, a polystyrene manufactured by Tosoh Corporation was usedfor a molecular weight range of Mw<1,000 and Mw>4×10⁶, and a polystyrenemanufactured by Pressure Chemical Co, was used for a molecular weightrange of 1,000≦Mw≦4×10⁶.

[Intrinsic Viscosity ([η])]

The intrinsic viscosity was measured at 135° C. using a decalin solvent.About 20 mg of a granulated pellet was dissolved in 15 ml of decalin,and a specific viscosity η_(sp) is measured in an oil bath at 135° C.Five ml of a decalin solvent is added to this decalin solution to dilutethe solution, and a specific viscosity η_(sp) is measured similarly.This diluting procedure is further repeated two times, and a η_(sp)/Cvalue when the concentration (C) is extrapolated to 0 is calculated andobtained as an intrinsic viscosity.

[η]=lim(η_(sp) /C)(C→0)

[Melt Flow Rate (MFR₁₀)]

This is a numerical value measured at 190° C. under 10 kg load by astandard method of ASTM D-1238.

[Density]

A strand after the measurement of MFR at 190° C. under 2.16 kg load washeat-treated at 120° C. for 1 hour, and gradually cooled to roomtemperature over 1 hour and, thereafter, the density was measured by adensity gradient tube method.

[Melting Point (Tm)]

By differential scanning calorimetry (DSC), a polymer sample was held at240° C. for 10 minutes, cooled to 30° C., held for 5 minutes, and,thereafter, a temperature of the sample was raised at 10° C./min. Themelting point was calculated from a crystal melting peak measured duringthe temperature raise.

Example 1

One liter of hexane was charged into an stainless autoclave having aninner volume of 2 liter which had been sufficiently replaced withnitrogen, the temperature in the system was raised to 145° C., andhydrogen was introduced to make a total pressure in the system reach 0.3MPa-G. Thereafter, the total pressure was retained at 3 MPa-G bycontinuously supplying only ethylene. Then, 0.3 mmol oftriisobutylaluminum, 0.04 mmol of N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate and 0.00005 mmol ofethylene(1-cyclopentadienyl)(fluorenyl)zirconium dichloride were chargedtherein with nitrogen to initiate polymerization. The polymerization wasperformed at 150° C. for 30 minutes. The polymerization was stopped byaddition of a small amount of ethanol to the system, and unreactedethylene was purged. The resulting polymer solution was dried at 80° C.overnight under reduced pressure. As a result, 20.0 g of an ethylenepolymer having [η] of 0.05 dl/g was obtained. The results are shown inTable 1.

Example 2

One liter of hexane was charged into a stainless autoclave having aninner volume of 2 liter which had been sufficiently replaced withnitrogen, the temperature in the system was raised to 145° C., andhydrogen was introduced to make a total pressure in the system reach 0.2MPa-G. Thereafter, the total pressure was retained at 3 MPa-G bycontinuously supplying only ethylene. Then, 0.3 mmol oftriisobutylaluminum, 0.04 mmol of N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate and 0.00005 mmol ofethylene(1-cyclopentadienyl)(fluorenyl)zirconium dichloride were chargedtherein with nitrogen to initiate polymerization. The polymerization wasperformed at 150° C. for 30 minutes. The polymerization was stopped byaddition of a small amount of ethanol to the system, and unreactedethylene was purged. The resulting polymer solution was dried at 80° C.overnight under reduced pressure. As a result, 32.0 g of an ethylenepolymer having [η] of 0.11 dl/g was obtained. The results are shown inTable 1.

Example 3

One liter of hexane was charged into a stainless autoclave having aninner volume of 2 liter which had been sufficiently replaced withnitrogen, the temperature in the system was raised to 145° C., andhydrogen was introduced to make a total pressure in the system reach 1.0MPa-G. Thereafter, the total pressure was retained at 3 MPa-G bycontinuously supplying only ethylene. Then, 0.3 mmol oftriisobutylaluminum, 0.04 mmol of N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate and 0.0001 mmol of ethylene(1-cyclopentadienyl)(3,6-t-butylfluorenyl)zirconium dichloride werecharged therein with nitrogen to initiate polymerization. Thepolymerization was performed at 150° C. for 30 minutes. Thepolymerization was stopped by addition of a small amount of ethanol tothe system, and unreacted ethylene was purged. The resulting polymersolution was dried at 80° C. overnight under reduced pressure. As aresult, 11.0 g of an ethylene polymer having [η] of 0.04 dl/g wasobtained. The results are shown in Table 1.

Example 4

One liter of hexane was charged into a stainless autoclave having aninner volume of 2 liter which had been sufficiently replaced withnitrogen, the temperature in the system was raised to 145° C., andhydrogen was introduced to make a total pressure in the system reach 0.2MPa-G. Thereafter, the total pressure was retained at 3 MPa-G bycontinuously supplying only ethylene. Then, 0.3 mmol oftriisobutylaluminum, 0.04 mmol of N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate and 0.00005 mmol ofethylene(1-cyclopentadienyl)(3,6-t-butylfluorenyl)zirconium dichloridewere charged therein with nitrogen to initiate polymerization. Thepolymerization was performed at 150° C. for 30 minutes. Thepolymerization was stopped by addition of a small amount of ethanol tothe system, and unreacted ethylene was purged.

Resulting polymer solution was dried at 80° C. overnight under reducedpressure. As a result, 16.1 g of an ethylene polymer having [η] of 0.22dl/g was obtained. The results are shown in Table 1.

Comparative Example 1

One liter of hexane was charged into a stainless autoclave having aninner volume of 2 liter which had been sufficiently replaced withnitrogen, the temperature in the system was raised to 145° C., andhydrogen was introduced to make a total pressure in the system reach 1.3MPa-G. Thereafter, the total pressure was retained at 3 MPa-G bycontinuously supplying only ethylene. Then, 0.3 mmol oftriisobutylaluminum, 0.04 mmol of N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate and 0.0002 mmol ofethylenebis(indenyl)zirconium dichloride were charged therein withnitrogen to initiate polymerization. The polymerization was performed at150° C. for 30 minutes. The polymerization was stopped by addition of asmall amount of ethanol to the system, and unreacted ethylene waspurged. The resulting polymer solution was dried at 80° C. overnightunder reduced pressure. As a result, 12.7 g of an ethylene polymerhaving [η] of 0.04 dl/g was obtained. The results are shown in Table 1.

Example 5

One liter of hexane was charged into a stainless autoclave having aninner volume of 2 liter which had been sufficiently replaced withnitrogen and, subsequently, 100 g of propylene was charged therein. Thetemperature in the system was raised to 145° C., the total pressure wasretained at 3 MPa-G by continuously supplying only ethylene. Then, 0.3mmol of triisobutylaluminum, 0.04 mmol of N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate and 0.0002 mmol ofethylene(1-cyclopentadienyl)(fluorenyl)zirconium dichloride were chargedtherein with nitrogen to initiate polymerization. The polymerization wasperformed at 150° C. for 30 minutes. The polymerization was stopped byaddition of a small amount of ethanol to the system, and unreactedethylene was purged. The resulting polymer solution was dried at 80° C.overnight under reduced pressure. As a result, 23.6 g of an ethylenepolymer having [η] of 0.56 dl/g was obtained. The results are shown inTable 2.

Example 6

One liter of hexane was charged into a stainless autoclave having aninner volume of 2 liter which had been sufficiently replaced withnitrogen and, subsequently, 80 g of propylene was charged therein. Thetemperature in the system was raised to 145° C., and hydrogen wasintroduced to make a total pressure in the system reach 0.1 MBa-G.Thereafter, the total pressure was retained at 3 MPa-G by continuouslysupplying only ethylene. Then, 0.3 mmol of triisobutylaluminum, 0.04mmol of N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate and0.0002 mmol of ethylene(1-cyclopentadienyl)(fluorenyl)zirconiumdichloride were charged therein with nitrogen to initiatepolymerization. The polymerization was performed at 150° C. for 30minutes. The polymerization was stopped by addition of a small amount ofethanol to the system, and unreacted ethylene was purged. The resultingpolymer solution was dried at 80° C. overnight under reduced pressure.As a result, 28.8 g of an ethylene polymer having [η] of 0.18 dl/g wasobtained. The results are shown in Table 2.

TABLE 1 Component (A) Component (B) Polymerization Polymerization AmountAmount Amount Hydrogen temperature time [η] Polymerization Kind (mmol)Kind (mmol) Kind (mmol) pressure *1 (° C.) (min) Yield (g) (dl/g)activity *2 Example 1 a 0.00005 I 00.04 TIBA 0.3 0.3 150 30 20 0.05400,000 Example 2 a 0.00005 I 00.04 TIBA 0.3 0.2 150 30 32 0.11 640,000Example 3 b 0.0001 I 00.04 TIBA 0.3 1.0 150 30 11 0.04 110,000 Example 4b 0.00005 I 00.04 TIBA 0.3 0.2 150 30 16.1 0.22 322,000 Comparative c0.0002 I 00.04 TIBA 0.3 1.3 150 30 12.7 0.04 63,500 Example 1 a:Ethylene(1-cyclopentadienyl)(fluorenyl)zirconium dichloride b:Ethylene(1-cyclopentadienyl)(3,6-tBu2fluorenyl)zirconium dichloride c:Ethylenebis(indenyl)zirconium dichloride I: N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate TIBA: Triisobutylaluminum *1: Mpa-G*2: g-PE/mmol-Zr

TABLE 2 Component Poly- Poly- (A) Component (B) merization merizationPoly- Amount Amount Amount Propylene Hydrogen temperature time Yield [η]Density merization Kind (mmol) Kind (mmol) Kind (mmol) (g) pressure *1(° C.) (min) (g) (dl/g) (kg/m³) activity *2 Example 5 a 0.0002 I 0.04TIBA 0.3 100.0 0 150 30 23.6 0.56 902 118,000 Example 6 a 0.0002 I 0.04TIBA 0.3 80.0 0.1 150 30 28.8 0.18 897 144,000 a:Ethylene(1-cyclopentadienyl)(fluorenyl)zirconium dichloride I:N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate TIBA:Triisobutylaluminum *1: Mpa-G *2: g-Polymer/mmol-Zr

Example 7

A glass autoclave having an inner volume of 1000 ml was equipped with athermometer, a gas blowing tube and a glass stirring wing, andsufficiently replaced with nitrogen. Thereafter, 250 ml of n-decane and250 ml of 1-decene were charged into the autoclave, and the temperaturein the system was raised to 90° C. while nitrogen was being flowntherein at an amount of 50 liter/hr. On the other hand, a magneticstirrer chip was placed into a flask with a branch having an innervolume of 30 ml, which had been sufficiently replaced with nitrogen, and0.002 mmol of a toluene solution ofethylene(1-cyclopentadienyl)(fluorenyl)zirconium dichloride as atransition metal compound, and 2 mmol of a toluene solution ofmethylaluminoxane (1.53M of Al) were added thereto, followed by stirringfor 30 minutes. The nitrogen flow to the glass autoclave was stopped,then hydrogen was flown at an amount of 20 liter/hr, and theaforementioned solution was added to initiate polymerization. During thepolymerization, hydrogen was continuously supplied at an amount of 20liter/hr, the polymerization was performed at 90° C. for 60 minutesunder normal pressure, and the polymerization was stopped by addition ofa small amount of isopropanol. The obtained polymer solution was addedin 300 ml of 1N hydrochloric acid, followed by stirring. This solutionwas transferred to a separating funnel, the organic layer was taken, theorganic layer was washed with water, and the solvent and unreacted1-decene were distilled off at 175° C. under reduced pressure (1 mmHg).The resulting transparent liquid polymer was 97.17 g, and thepolymerization activity was 48.59 kg-polymer/mmol-Zr/hr. The polymer wasanalyzed. [η] was 0.04 dl/g, Mw was 4,250, Mn was 2,320, and Mw/Mn was1.64. The results are shown in Table 3.

Example 8

The same procedures as those of Example 7 were performed except that thepolymerization temperature was changed to 60° C., and the amount ofhydrogen was changed to 10 liter/hr.

The weight of the resulting transparent liquid polymer was 74.64 g, andthe polymerization activity was 37.32 kg-polymer/mmol-Zr/hr. The polymerwas analyzed. [η] was 0.09 dl/g, Mw was 13,360, Mn was 7, 220, and Mw/Mnwas 1.85. The results are shown in Table 3.

Example 9

The same procedures as those of Example 7 were performed except that thepolymerization temperature was changed to 70° C., and the amount ofhydrogen was changed to 50 liter/hr.

The weight of the resulting transparent liquid polymer was 77.34 g, andthe polymerization activity was 38.67 kg-polymer/mmol-Zr/hr. The polymerwas analyzed. [η] was 0.06 dl/g, Mw was 9.720, Mn was 5,170, and Mw/Mnwas 1.88. The results are shown in Table 3.

Example 10

A glass autoclave having an inner volume of 1000 ml was equipped with athermometer, a gas blowing tube and a glass stirring wing, andsufficiently replaced with nitrogen. Thereafter, 250 ml of n-decane and250 ml of 1-decene were charged into the autoclave, and the temperatureof the system was brought to 60° C. while nitrogen was being flowntherein at an amount of 50 liter/hr. The flow nitrogen into the glassautoclave was stopped, hydrogen was flown at an amount of 10 liter/hr.Thereafter, 2 mmol of an n-decane solution of triisobutylaluminum wasadded. Then, 0.002 mmol of a toluene solution ofethylene(1-cyclopentadienyl)(fluorenyl)zirconium dichloride as atransition metal compound was added and, finally, 0.04 mmol of a toluenesolution of N,N-dimethylaluminium tetrakis(pentafluorophenyl)borate wasadded to initiate polymerization. During the polymerization, hydrogenwas continuously supplied at an amount of 10 liter/hr, thepolymerization was performed at 60° C. for 60 minutes under normalpressure, and the polymerization was stopped by addition of a smallamount of isopropanol. The polymer solution was added in 300 ml of 1Nhydrochloric acid, followed by stirring. This solution was transferredto a separating funnel, the organic layer was taken, thereafter, theorganic layer was washed with water, and the solvent and unreacted1-decene were distilled off at 175° C. under reduced pressure (1 mmHg).The weight of the resulting transparent liquid polymer was 106.20 g, andthe polymerization activity was 53.10 kg-polymer/mmol-Zr/hr. The polymerwas analyzed. [η] was 0.13 dl/g, Mw was 22,670, Mn was 13,700, and Mw/Mnwas 1.65. The results are shown in Table 3.

Example 11

A glass autoclave having an inner volume of 1000 ml was equipped with athermometer, a gas blowing tube and a glass stirring wing, andsufficiently replaced with nitrogen. Thereafter, 400 ml of n-decane and100 ml of 1-decene were charged into the autoclave, and a temperaturewas brought to 60° C. while nitrogen was being flown therein at anamount of 50 liter/hr. On the other hand, a magnetic stirrer chip wasplaced into a flask with a branch having an inner volume of 30 ml whichhad been sufficiently replaced with nitrogen, and 0.002 mmol of atoluene solution of ethylene(1-cyclopentadienyl)(fluorenyl)zirconiumdichloride as a transition metal compound, and 2 mmol of a toluenesolution of methylaluminoxane (1.53M of Al) were added thereto, followedby stirring for 30 minutes. The nitrogen flow into the glass autoclavewas stopped, ethylene was flown for 5 minutes at an amount of 50liter/hr, hydrogen was flown at an amount of 10 liter/hr whilemaintaining a flow rate of ethylene, and the aforementioned solution wasadded to initiate polymerization. During the polymerization, ethyleneand hydrogen were continuously supplied at an amount of 50 liter/hr and10 liter/hr, respectively. The polymerization was performed at 60° C.for 60 minutes under normal pressure, and the polymerization was stoppedby addition of a small amount of isopropanol. The polymer solution wasadded in 300 ml of 1N hydrochloric acid, followed by stirring. Thissolution was transferred to a separating funnel, the organic layer wastaken, the organic layer was washed with water, and the solvent andunreacted 1-decene were distilled off at 175° C. under reduced pressure(1 mmH). The weight of the resulting transparent liquid polymer was49.49 g, and the polymerization activity was 27.74kg-polymer/mmol-Zr/hr. The polymer was analyzed. [η] was 0.16 dl/g, Mwwas 27,060, Mn was 17,980, and Mw/Mn was 1.51. The results are shown inTable 3.

Example 12

The same procedures as those of Example 7 were performed except that1-decene as a monomer was changed to 1-octene, the polymerizationtemperature was changed to 50° C., and the amount of hydrogen waschanged to 10 liter/hr.

The weight of the resulting transparent liquid polymer was 49.95 g, andthe polymerization activity was 24.98 kg-polymer/mmol-Zr/hr. The polymerwas analyzed. [η] was 0.10 dl/g, Mw was 16,700, Mn was 9,380, and Mw/Mnwas 1.63. The results are shown in Table 3.

Example 13

The same procedures as those of Example 7 were performed except that1-decene as a monomer was changed to 1-dodecene, the polymerizationtemperature was changed to 50° C., and the amount of the hydrogen waschanged to 10 liter/hr.

The weight of the resulting transparent liquid polymer was 29.59 kg, andthe polymerization activity was 14.80 kg-polymer/mmol-Zr/hr. The polymerwas analyzed. [η] was 0.10 dl/g, Mw was 18,360, Mn was 11,400, and Mw/Mnwas 1.61. The results are shown in Table 3.

Example 14

The same procedures as those of Example 7 were performed except that1-decene as a monomer was changed to 1-tetradecene, the polymerizationtemperature was changed to 50° C., and the amount of hydrogen waschanged to 10 liter/hr.

The weight of the resulting transparent liquid polymer was 20.40 kg, andthe polymerization activity was 10.20 kg-polymer/mmol-Zr/hr. The polymerwas analyzed. [η] was 0.11 dl/g, Mw was 23,570, Mn was 14,460, and Mw/Mnwas 1.63. The results are shown in Table 3.

Example 15

The same procedures as those of Example 7 were performed except thatethylene(1-cyclopentadienyl)(fluorenyl)zirconium dichloride was changedto ethylene(1-cyclopentadienyl)(2,7-di-tert-butyl-fluorenyl)zirconiumdichloride, the polymerization temperature was changed to 60° C., andthe amount of the hydrogen was changed to 10 liter/hr.

The weight of the resulting transparent liquid polymer was 28.25 kg, andthe polymerization activity was 14.13 kg-polymer/mmol-Zr/hr. The polymerwas analyzed. [η] was 0.08 dl/g, Mw was 12,120 Mn was 7,410, and Mw/Mnwas 1.64. The results are shown in Table 3.

Example 16

The same procedures as those of Example 7 were performed except thatethylene(1-cyclopentadienyl)(fluorenyl)zirconium dichloride was changedtoethylene(1-cyclopentadienyl)(octamethyloctahydrodibenzofluorenyl)zirconiumdichloride, the polymerization temperature was changed to 80° C., andthe amount of the hydrogen was changed to 35 liter/hr.

The weight of the resulting transparent liquid polymer was 47.51 kg, andthe polymerization activity was 23.76 kg-polymer/mmol-Zr/hr. The polymerwas analyzed. [η] was 0.07 dl/g, Mw was 9,910, Mn was 5,860, and Mw/Mnwas 1.69. The results are shown in Table 3.

Example 17

The same procedures as those of Example 7 were performed except thatethylene(1-cyclopentadienyl)(fluorenyl)zirconium dichloride was changedto ethylene(1-cyclopentadienyl)(octamethyloctahydrodibenzofluorenyl)zirconiumdichloride, 1-decene as a monomer was changed to 1-dodecene, thepolymerization temperature was changed to 50° C., and the amount ofhydrogen was changed to 35 liter/hr.

The weight of the resulting transparent liquid polymer was 45.30 kg, andthe polymerization activity was 22.65 kg-polymer/mmol-Zr/hr. The polymerwas analyzed. [η] was 0.07 dl/g, Mw was 8,720, Mn was 4,900, and Mw/Mnwas 1.78. The results are shown in Table 3.

Example 18

The same procedures as those of Example 7 were performed except thatethylene(1-cyclopentadienyl)(fluorenyl)zirconium dichloride was changedto (1-cyclopentadienyl)(ocatamethyloctahydrodibenzofluorenyl)zirconiumdichloride, 1-decene as a monomer was changed to 1-tetradecene, thepolymerization temperature was changed to 50° C., and the amount ofhydrogen was changed to 35 liter/hr.

The weight of the resulting transparent liquid polymer was 39.20 kg, andthe polymerization activity was 19.60 kg-polymer/mmol-Zr/hr. The polymerwas analyzed. [η] was 0.06 dl/g, Mw was 9,680, Mn was 6,150, and Mw/Mnwas 1.57. The results are shown in Table 3.

TABLE 3 Component Monomer charging amount (A) Component (B) TemperatureTime Ethylene Hydrogen 1-Decene 1-Octene Example Kind mmol Kind mmolKind mmol (° C.) (min) (1/h) (1/h) (ml) (ml) Example 7 a 0.002 — — MAO 290 60 — 20 250 — Example 8 a 0.002 — — MAO 2 60 60 — 10 250 — Example 9a 0.002 — — MAO 2 90 60 — 50 250 — Example 10 a 0.002 I 0.04 TIBA 2 6060 — 10 250 — Example 11 a 0.002 — — MAO 2 60 60 50 10 100 — Example 12a 0.002 — — MAO 2 50 60 — 10 — 250 Example 13 a 0.002 — — MAO 2 50 60 —10 — — Example 14 a 0.002 — — MAO 2 50 60 — 10 — — Example 15 d 0.002 —— MAO 2 60 60 — 10 250 — Example 16 a 0.002 — — MAO 2 80 60 — 35 250 —Example 17 a 0.002 — — MAO 2 50 60 — 35 — — Example 18 a 0.002 — — MAO 250 60 — 35 — — Monomer charging amount 1-Dodecene 1-Tetra decene YieldPolymerization [η] GPC Example (ml) (ml) (g) activity *1 (dl/g) Mn MwMw/Mn Example 7 — — 97.17 48.59 0.04 2,320 4,250 1.64 Example 8 — —74.64 37.32 0.09 7,220 13,360 1.85 Example 9 — — 77.34 38.67 0.06 5,1709,720 1.88 Example 10 — — 106.20 53.10 0.13 13,700 22,670 1.65 Example11 — — 49.49 24.74 0.16 17,980 27,060 1.51 Example 12 — — 49.95 24.980.10 9,380 16,700 1.63 Example 13 250 — 29.59 14.80 0.10 11,400 18,3601.61 Example 14 — 250 20.40 10.20 0.11 14,460 23,570 1.63 Example 15 — —28.25 14.13 0.08 7,410 12,120 1.64 Example 16 — — 47.51 23.76 0.07 5,8609,910 1.69 Example 17 250 — 45.30 22.65 0.07 4,900 8,720 1.78 Example 18— 250 39.20 19.60 0.06 6,150 9,680 1.57 a:Ethylene(1-cyclopentadienyl)(fluorenyl)zirconium dichloride d:Ethylene(1-cyclopentadienyl)(2,7-di-tert-butyl-fluorenyl)zirconiumdichloride e:Ethylene(1-cyclopentadienyl)(octamethyloctahydrodibenzofluorenyl)zirconiumdichloride I: N,N-dimethylanilinium tetrakis(pentafluorophenyl)borateMAO: Methylaluminoxane TIBA: Triisobutylaluminium *1:kg-Polymer/mmol-Zr/hr

1. An olefin polymerization catalyst suitable for preparing a lowmolecular weight olefin (co)polymer by homopolymerizing orcopolymerizing an olefin, which comprises: (A) a Group 4 transitionmetal compound represented by the following formula (1), and (B) atleast one compound selected from the group consisting of (B-1) anorganometallic compound, (B-2) an organoaluminum compound, (B-3) anorganoaluminum oxy-compound, and (B-4) a compound that reacts with theGroup 4 transition metal compound (A) to form an ion pair;

wherein R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹², R¹³ and R¹⁴are independently selected from the group consisting of hydrogen, ahydrocarbon group, and a silicon-containing group, and are the same ordifferent; and each adjacent pair of substituents R¹ to R¹⁴ may be takentogether to form a ring; M is Ti, Zr or Hf; Y is a Group 14 atom; each Qis independently selected from the group consisting of: a halogen, ahydrocarbon group, a neutral conjugated or non-conjugated diene having10 or fewer carbon atoms, an anionic ligand, and a neutral ligand thatcan be coordinated with a lone electron pair; n is an integer of from 2to 4; and j is an integer of from 1 to
 4. 2. The olefin polymerizationcatalyst according to claim 1, wherein the Group 4 transition metalcompound represented by the general formula (1) is a Group 4 transitionmetal compound represented by the said formula (1′).
 3. A Group 4transition metal compound represented by the following formula (1′);

wherein R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹ and R¹² areindependently selected from the group consisting of a hydrogen atom, ahydrocarbon group, and a silicon-containing group, and may be the sameor different; each of R¹³, R¹⁴, R¹⁵ and R¹⁶ is independently a hydrogenatom or a hydrocarbon group; n is an integer of from 1 to 3 and when nis 1, not all of the R¹ to R¹⁶ are hydrogen atoms, and each of the R¹ toR¹⁶ may be the same or different; each adjacent pair of substituents R⁵to R¹² may be taken together to form a ring; R¹³ and R¹⁵ may be takentogether to form a ring, or the pair of R¹³ and R¹⁵ and the pair of R¹⁴and R¹⁶ may be taken together to form rings simultaneously; each of Y¹and Y² is a Group 14 atom, and may be the same or different; M is Ti, Zror Hf; each Q is independently selected from a group consisting ofhalogen, a hydrocarbon group, an anionic ligand and a neutral ligandthat can be coordinated with a lone electron pair; and j is an integerof from 1 to 4].
 4. The Group 4 transition metal compound according toclaim 3, wherein n is 1 or 2, and each of Y¹ and Y² is a carbon atom ora silicon atom, in the formula (1′).
 5. The Group 4 transition metalcompound according to claim 3, wherein two or more of the substituentsR⁶, R⁷, R¹⁰ and R¹¹ are hydrocarbon groups having 1 to 20 carbon atoms,in the formula (1′).
 6. The group 4 transition metal compound accordingto claim 3, wherein R⁶ and R⁷ are taken together to form an aliphaticring, and R¹⁰ and R¹¹ are taken together to form an aliphatic ring, inthe formula (1′).